In the past, tubing strings have employed various devices which have needed pressure chambers for actuation of various components. In some of these layouts, a separate connection outside the tubing string is provided for hydraulic control pressure. This pressure is used to selectively actuate a subsurface safety valve, depending on the configuration. Occasionally, the control components in the hydraulic circuit, for actuation of such downhole components as a subsurface safety valve, fail. For example, the hydraulic piston that is actuated by the control circuit, which is in fluid communication with an annular chamber, occasionally sticks or experiences seal failure. When this occurs, it is not possible to use the hydraulic forces in the control circuit to actuate the subsurface safety valve, or some other downhole component as required. When these circumstances occur, it is desirable to lower a substituted component through the tubing and position it appropriately to accomplish the task of the part rendered inoperative due to control circuit failure. At the same time, it is desirable to use the hydraulic control pressure to actuate this newly inserted component in the tubing or wellbore.
When these situations occur, it has become desirable to lower a penetrating tool to the desired depth and bore laterally into the hydraulic control circuit chamber. In order to facilitate the fluid communication into the control circuit, an annular chamber is provided so that upon reaching the proper depth, radial puncture in any direction will assure fluid communication into the annular chamber. Stated differently, if the control circuit flowpath extending within the tubular were strictly longitudinal, the puncture device would have to be properly oriented so that when it was actuated to perform a radial puncture, it would be in alignment with the longitudinal flowpath of the control circuit.
In the past, sealing annular control circuit chambers has been and continues to be of concern. Prior designs have employed resilient seals on at least one side of the chamber. These resilient seals suffered from difficulty in assembly and reduced reliability.
Accordingly, one of the objects of the present invention is to provide an annular chamber, such as those used in control circuits where the annular chamber extends in the tubular goods and is sealed internally and externally by metal-to-metal seals. It is a further object of this invention to eliminate resilient seals for sealing annular chambers used in control circuits or other application in tubular goods for downhole use.